Measurement and control of RF power is a critical consideration when designing a wireless transmitter. High-power RF amplifiers rarely operate in open-loop mode, that is, where the power to the antenna is not in some way regulated. External factors, such as regulatory requirements on power transmitted, network robustness, and the need to co-exist with other wireless networks, require tight control of transmitted power. In addition to these external requirements, precise RF power control can result in improved spectral performance and can save cost and energy in the transmitter's power amplifier. In order to regulate its transmitted power, some form of calibration of the transmitter output power can be performed.